Hydraulic underreamer



July 3, 1928.

Filed Jan. 28, 1926 2 Shee'ts-Sheet l Patented July 3, 192s.

UNITED STATES PATENT oFFlcE.

HYDRAULIC UNDEBBEAME?. I

Appnauon nica January 2s, 192s. serial m. 114,342.

This invention relates to improvements in hydraulic rotary underreamersused 1n well drilling, and may be considered as an improvement over theunderreamer dlsclosed in my prior Patent, No. 1,548,578, lssued August4, 1925.

An object of this invention is to prov1de an improvedhydraulicallyloperated underreamer which is of improved construction andwhich is so designed that it is very diliicult for parts to get out oforder.

Another object of this invention is to provide an improved cutterconstruction upon an underreamer.

A further object of this invention is to provide an improved mechanismfor admitting fluid to the interior of the lower pipe or drill pipeabove the tool, so that pressure will not build up within the toolduring lowering to cause the reamerto be expanded when itis not sointended.

With the foregoing and other objects in view which will be made manifestin the following detailed description and specifically pointed out inthe appended claims, reference is had to the accompanyin drawings for anillustrative embodiment o the invention, wherein:

Figure l is a vertical section through the improved underreamer shown infully expanded position,

Fig. 2 is a view similar to Fig. 1, illustrating the reamer in fullycontracted position.

Fig.4 3 is a partial 'View in section illustrating the details ofconstruction of the cutters and blocks on which the cutters are mounted,thev reamer in this view being shown in fully expanded position,

Fig. 4 is a partial view in side elevation taken substantially in thedirection of the arrow 4 upon Fig. 3,

Fi 5 is a.' horizontal section taken substantlally on the line 5-5 ofFig. 3,

Fig. 6 is a view similar to Fig. 5 illustrating the reamer in contractedposition, and may be considered as a horizontal section taken upon theline 6-6 of Fig. 2,

Fig. 7 is a vertical section illustrating the details of construction ofthe valve and Referring to the accompanying drawings wherein similarreference characters desig.

ports which admit fluid to the interior of" nate similar partsthroughout, the-details of construction of the reamer proper are asfollows: The reamer consists of a cylindrical body 10 having an interiorcylindrical surface. In this body there are formed two diametrical slots11, and within it there is positioned a conical wedge or mandrel 12, inwhich is formed a longitudinal bore 13. This wedge isthreadedlyconnected to the body 10, as indicated at 14, and constitutesa wash pipe terminating inl a cylindrical section 15. Blocks 16 arevertically slidable in the two slots 11. These blocks have their innerfaces engageable upon the conical wedge or mandrel l12 so that when theyare lifted, they will `be expanded or forced radially outwardly throughthe slots 11. Each of the blocks' has its inner face presenting aconical surface which is complementary to the conical surface on thewedge 12 when the blocks are in their uppermost position. They are alsoprovided with lateral wings 17 whlch extend laterally beyond the sidesof the slots 11, and these lateral wings have their forward surfacescylindrical in shape so that they will lit against the interiorcylindricalsurface of the body l0 when the blocks are in their uppermostposition. In each of the blocks there is positioned a vertical pin 18which is locked in place as by a pin 19, and a cutter or reamer 20 isrotatabl mounted upon each pin 18. A bore 21 is ormed in each block 16so that a spike or punch can be inserted therein to knock loose thevertical pin 18 whenever it is desired to replace the cutters 20 or toreplace the pins 18.

Adjacent the lower end of each of the blocks 16 there is formed adownwardly and inwardly inclined pin 22 which is threaded.

A bushing 23 is threaded onto this pin and a cutter 24 is rotatablymounted on this bushing between washers 25. Each of the cutters 24,because of the above described construction, is rotatable about axeswhich are upwardly and outwardly inclined. They are so formed as toprovide a surface 26 which on the lower portion of the cutter isapproximatelyl vertical, and also a 4surface 27 which on the lowerportion of the cutter is approximately horizontal. It will be understoodthat these cutters do the major portion of the cutting, the cutters 20being used mainly for merely smoothing up the hole thus reamed.

Supplemental blocks 28 are secured to the pins 22 as by cap screws 29,and these-blocks are similar in cross section to the bloclis 16 in thatthe have the lateraljwings 17. The length of the slots 11 isapproximately twice the overall dimension of the'blocks 16 -to- 5get-her with the supplemental blocks 28.

` within the slots 11, a cylindrical AAs a means for raising the blocks16 together with the' supplemental blocks 28 is slidable within the bodybelow t e blocks l and arranged about-the .conical wedge or mandrel 12.This piston is illustrated as `being provided with a cup or packingleather 31 held in place by a ring 32 which is fastened by screws 33. Onthe interior of the l body there is positioned a brass or bronze Wedge12, when the pistoni-$0 is in'ts upper-- liner 34 against which thepacking leather 31 bears. The interiorof the piston 30 has a conicalsurface which is complementary to the conical surface of the mandrel orconical most position, that is, when)y it hasflifted the blocks 16 tothat position` in which encounter the upper ends of theslots 11. In thelower end o the bodylO there is screwed 25, a sub 35 having a divisionweb or a blanked 30 through, but at the same time causing wardly throughthe bore 13, the pressure drei 12, win@ developed within the body`10will cause the piston-30 to rise and thus lift the blocks 16. It will benoted that when the blocks are completely lifted their upper ends engagethe tops 'of the slots 11the forward surfaces of the wings 17 engage theinterior surface of the body while the inner surfaces of the blocks 16engage and t the conical wedge 12 and also the piston 30 fits theconical wedge 12, thus forming a tight, rigidi construction during thereaming so'that there will be no wobbling or loosening of the parts.

On lowering theunderreamer into the hole by the drill pipe D it will beunderstood that the well hole is fullof liquid and it will flow upwardlythrough the fbores 37 in the 'blanked off ortion 36 of the sub 35. Be-

cause of the act that a quick lowering ofthe reamer into the hole mightcause this uid to.build up a pressure on the under side of the piston30, causing the reamer to be expanded during the lowering, there isprovided a particular valve construction at the upper end of the reamerwhich will admit fluid from the hole intothe drill pipe D to eliminatethis.

In the bodyl of the conical wedge orinanextends above the cylindricalbody 10,there' are formed a plurality of radial Aports 38, and on itsinterior there is iston 30 they' formed an annular recess 39 with whichthe ports communicate. On theinterior of the upper end of the conicalwedge or mandrel 12 there is screwed a valve seat 40 having a vertical`bore 41 therethrough and providing a seat for the ball check valve 42.The ball check valve 42 is maintained adjacent its seat by a cage 43.The lower end of the bore 41 is closed by a plug 44,. and in the body 0fthe valve seat 40 there are formed radial ports 45 which communicatewith the recess 39. As clearly indicated in Fig. 8,

vertical passages 46 are formed in the body..

of the fluid will be caused to lill the drill pipe D b flowing throu hthe ports 38 into the annu ar recess 39 and through the ports 45,fiowing upwardly through the bore 41 beneath the check valve 42. Afterthe device vhas been lowered into the well, fluidis forced downwardlywithin the drill pipe, the check valve 42 again seats and the fluid isall caused to-flow through the vertical passages 46. In. this manner itwill be noted that fluid can enter the drill pipe D above the tool sothat no pressure will be developed on the under side of the piston 30,causing it to be lifted during the lowering into the well hole.

From the above described construction it will be appreciated that anVimproved hydraulically operated underreamer is provided which issimplein construction and very rugged in design. Furthermore, when the reameris in expanded position, all parts will be snugly fittin or restingagainst each owever, on lowering the reamer into the well, fluid mayfiow upwardly within thepassages 37, but the larger portionv other,forming a so id structure duringthe" reaminv. c c

It will be understood that variousI changes may be made in the detail ofconstruction without departing from the spirit or scope of the inventionas defined b the a ded l y y Iclaim:

- 1. An underreamer comprising a slotted' ally be ond the sides of theslots between 'the w and thebody, a Vpiston within the body below saidblocks,r and means for causing fluid discharged through said Wedge tobuild up a pressure beneath said piston, causing itv to lift said blocksinto engagement with said wedge, so that they will be expanded thereby.

l2. An underreamer comprising a slotted body presenting an interiorcylindrical surface, a conical wedge having a bore therethrough disposedin said body, blocks carrying cutters slidable in said slots havingtheir inner sides en agea'ble upon the wedge, a piston Vdisposedg withinthe body and about the lower end of said wedge, said piston beingarranged below said locks, and means for causing fluid dischargedthrough said wedge to buildup a pressure beneath said piston, causing itto `lift said bloclis into engagement with said wedge, so that they willbe expanded thereby.

3. An underreamer comprising a slotted body presenting an interiorcylindrical surface, a conical wedge having a bore theretliroughdisposed in said body, blocks carrying cutters slidable in said slotshaving their c 'i inner sides engageable upon`the wedge, a

wedge to build upa.

piston disposed within the body and about the lower end of said Wedge,sald piston being arranged below said blocks, and means for causingfluid discharged through said ressure beneath said piston, causing it toli said blocks into engagement with said wedge, so that they will beexpanded thereby, sald blocks having lateral wings extending laterallybeyond the iddes of the slots between the Wedge and the i 4.yAnunderreamer comprising a slotted body-presenting an interior cylindricalsurface, a conical wedge having a bore therethrough disposed in saidbody, blocks carrying cutters slidable in said slots having their innersides engageable upon the wedge, said blocks having lateral wingsextending laterally be ond the sides of the slots between the wedge andthe body, a piston disposed Within the body below said blocks, and meansfor causing fluid discharged through said wedge to build up a pressurebeneath said piston, causing it to lift said blocks into engagement wlthsaid wedge, so that they will be expanded thereby, said piston having aconical bore therein complemenv tary tothe surface of the wedge.

5. An underreamer comprising `a slotted, hollow body, a Wedge disposedin said body, blocks carr ing cutters slidable in the slots, said blockseing engageable upon said wedge so as to be expanded thereby andcarrying lateral wings in sliding en agement with the innercircumference o the body to prevent the blocks from being withdrawn fromthe slots, apiston slidable in `the body below the blocks, said wedgehavving a bore therethrough through which fluid may be discharged, andmeans for causing the fluid discharged through said wedge to build up apressure below the piston to cause the piston to lift the blocks intoengagethrough the valve'. seat for the purpose described.

7. In a hydraulically operated well` drilling tool, a tubular bodythrough which fluid is adapted to be forced, a valve seat mounted insaid body, a Valve adapted to seat thereon, means closing the bottom ofthe valve seat, there being passages formed in the tubular body and inthe valve seat establishing communication between the exterior of thebody and the interior of the valve seat above said closing means, therebeing passages formed in the valve seat forming by-passes about thevalve permitting fluid to be forced through the valve seat Within saidtubular body.

In testimony whereof I have signed my name to this specification.

B. F. BLANCHARD.

below the valve and passages arranged-

